The invention relates to a multi-stage hurdle-type reactor, for catalytic, exothermic and endothermic chemical processes, a heat exchanger being co-ordinated with each catalyser bed. In the case of a reaction plant of this kind, the catalyst used for performing a chemical reaction wigh a gas, which commonly consists of a granular mass, must be removed after some time for regeneration or replacement.
Different systems already exist for replacing the catalyst for reactors, which are especially intended and appropriate for a tube-type plant (e.g. according to DT-PS 1,161,257 and DT-PS 2,165,266).
A catalyst which is very porous and brittle is frequently applied in the production of benzene from coal gas. A catalyst of this kind, which must be replaced comparatively frequently, is appropriately applied within a hurdle-type reactor, orders of magnitude of 30m.sup.2 for the total surface area of a hurdle or shelf and of 400m.sup.3 for the total quantity of the catalyst, occurring in practice. These numerical data merely serve as examples and may either not be reached, or exceeded, within the scope of the invention.